There is a middle ground, I agree. The middle ground is to let people do as they will in the user space, and merely use reason and argument to teach people over time why one ought not use Wikipedia userpages for political or other campaigns.... while at the same time saying, no, really, the template namespace is not for that, that we do not endorse this behavior. This is the solution that the Germans have put into effect with great results.
But it seems that the namespace proposal goes a bit further than what you need to achieve what you want to achieve. Let me quote you on something: "The text of WP:UPP is filled with what one can and cannot say, specifically, All userbox templates that show a POV or are not directly related to wikipedia will be deleted after a period of time. Note that a user subpage that is transcluded without substitution by multiple users is considered a 'template.This is like saying, "You may have pamphlets, but you may not mechanically print and distribute them. This is not an infringement of free speech". To put it kindly, this is counter-intuitive."
And a quick note to certain admins: This is not Template space. This is Userspace. NPOV and T1 do not apply here. Read Jimbo's comments above. Thank you.
Obey WP:USER, WP:CIVIL, and WP:NPA; i.e., no personal attacks, no hate boxes, no fair use or copyrighted images. And please, no vandalism. I know how to find WP:AIV, so you don't want to go down that road.